The field of drying powders is concerned with specific problems that may occur due to the potential flammability in form of dust explosions of such powders, and a drying process should be carefully monitored to estimate the risk of explosions/fires in the dryer.
DK177236B1 discloses an apparatus for online sampling from a product stream, where the sampling is carried out in an ongoing manner by placing a container with an opening directly into a product stream, wherein the flowing product is collected in said container for determining one or more physical conditions, for example weight relative to volume, humidity, size and/or colour. The apparatus comprises at least one displaceable container, and means for displacing the container.
EP2243015B1 discloses a device for sampling from a product stream, where the sampling is carried out in an ongoing manner and wherein the product is collected in a sample container to determine physical conditions, for example weight relative to volume.
A commercial sampling apparatus known as the POWDEREYE™ is also known.
The known devices for sampling have in common that they are not suited for taking samples in explosive environments where there can be a mixture of air and flammable substances under atmospheric conditions, which if ignited could spread in the remaining product. The flammable material may for example be in the form of gasses, vapour, mist and/or dust.
The known devices for sampling thus do not satisfy the safety requirements for use in explosive atmospheres, as none of the devices include explosion zones.
Within the field of powder processing it is further of interest to estimate the flowability of a sample of particles. Estimation of the flowability of a sample of particles has been suggested by Lumay, Boschini, Traina, Bontempi, Remy, Cloots & Vandewalle (2012, Powder Technology, 224: 19-27). The method involves placing a sample of particles in a cylinder, placing a light object on top of the sample to keep it flat, and letting the cylinder go through a number of cycles of lifting the cylinder and letting it fall the same distance, and measuring the height of the sample after each fall. The method is not suited for integration into an apparatus for on-line or in-line monitoring of a process.